I'm sure the instructors probably have better advice but, going through some strumming problems of my own, I have a couple of thoughts. You mentioned going through pretty much everything, but perhaps you can take a moment to reset. Take a deep breath (again, I'm sure) and reset -

1. Choose a really thin pick. It'll sound a bit "sloppy" but that's ok for now.

2. Check (for probably the 100th time) on how you're holding the pick. This turned out to be the main problem for me: improper "pick holding". Really. There are a number of places in the lessons that talk about holding the pick.

3. You're not going to like this, but set the metronome on a low setting, make an "E" chord and ONLY upstrum. Slowly. Make sure the metronome is on a setting you can easily hit.

4. Chances are the pick is turning because your grip is failing and (possibly) your attack is not consistent.

5. Check on how you're anchoring your arm to the guitar. If you're not anchoring somewhere, your attack will most likely be erratic. If your attack is erratic, your fingers will have problems holding the pick.

6. Is your upstrum with only your wrist, only your elbow, or a combination? Perhaps for a while, it may pay off to strum with only the wrist or only the elbow (keeping a steady wrist). At least long enough to get your attack ok. I solved one of my strumming problems (and cleaned up my attack) by only strumming from the elbow for a while.

7. Set a goal of (perhaps) 10 upstrokes with the metronome without the pick rotating. Stop after 10. Rest a minute then do it again. If you can do 10, come back tomorrow and try 12.

Sounds a little robotic I know. Perhaps you can pick a slow beat song, hold the root chord with your right hand and only upstroke on the "one" beat. I dunno - something to liven things up.

Just some thoughts. Know that you're not the only one out there who is "strumming challenged".

Never stop playing

RW